Chlorine evolution reaction electrocatalysis on RuO2(110) and IrO2(110) grown using molecular-beam epitaxy

Ding-Yuan Kuo; Hanjong Paik; Jocienne N Nelson; Kyle M Shen; Darrell G Schlom; Jin Suntivich

doi:10.1063/1.5051429

Chlorine evolution reaction electrocatalysis on RuO₂(110) and IrO₂(110) grown using molecular-beam epitaxy

J Chem Phys. 2019 Jan 28;150(4):041726. doi: 10.1063/1.5051429.

Authors

Ding-Yuan Kuo¹, Hanjong Paik¹, Jocienne N Nelson², Kyle M Shen², Darrell G Schlom¹, Jin Suntivich¹

Affiliations

¹ Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
² Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.

PMID: 30709296
DOI: 10.1063/1.5051429

Abstract

We report the electrocatalysis of the chlorine evolution reaction (CER) on well-defined RuO₂(110) and IrO₂(110) surfaces. RuO₂ and IrO₂ are known for their capabilities to catalyze the CER. Until now, the CER measurements have only been reported on well-defined RuO₂ surfaces and only at high Cl^- concentrations. We present the CER measurement and the role of Cl^- at lower concentration on single-orientation RuO₂(110) and IrO₂(110) films. We find that RuO₂(110) is two orders of magnitude more active than IrO₂(110). Moreover, we observe the correlation between the CER activity and the O_ad formation potential on RuO₂ and IrO₂, supporting the prior suggestion that the O_ad is the active site for the CER. We further use the reaction order analysis to support the Volmer-Heyrovsky mechanism of the CER, which was previously suggested from the Tafel slope analysis. Our finding highlights the importance of the surface O_ad species on oxides for the CER electrocatalysis and suggests the electrochemical formation of Cl_ad on O_ad (for example, Cl^- + O_ad ↔ OCl_ad + e^-) as the crucial step in the CER electrocatalysis.